Commonly available punch and die tools for press brakes are made with variable working heights so that combined working heights of mating punch and die sets often differ. Even though such tools may be in stock and available for use, sets of tools with different combined working heights cannot be arranged at different work stations along the length of a press brake. This is a serious disadvantage. Press brakes have grown larger and longer and are readily able to accommodate multiple work stations along their length, so long as the combined working height of all the mating tool sets is equal. Such multiple work stations are often desirable so that all the forming operations required for a single work piece can be performed sequentially at different work stations of a press brake. This allows all the necessary forming operations to be completed while the work piece is being handled once, which can make production much more efficient.
If all the punch and die tool sets mounted in a press brake have a common or equal combined working height, then each working stroke of the ram of the press brake can bring the tools at each work station into working juxtaposition without crashing tools together. A possible solution that has been used for mounting of punch and die tools at multiple work stations along a press brake is to have tools custom made to achieve equal combined working heights for each tool set. This solution has two serious disadvantages, though. Custom made forming punches or dies for a press brake cost much more than ordinary tools, which may even be available from an established stock. Secondly, custom tooling involves delay while tools are made to the required working height, and the delay slows down production. Both of these problems increase tool costs and add to production expense.
This invention solves the problem of mounting multi-work station press brake tooling having different combined working heights so as to avoid the need for custom made tooling. The invention applies its solution to a European-style press brake having tool holders for mounting forming punches on a ram of the press brake to move into working juxtaposition with dies mounted on a bed of the press brake. An example of such a press brake is shown in U.S. Pat. No. 5,619,885.